CVE-2025-6751
📋 TL;DR
A critical buffer overflow vulnerability in Linksys E8450 routers allows remote attackers to execute arbitrary code by sending specially crafted HTTP POST requests to portal.cgi. This affects all Linksys E8450 routers running firmware version 1.2.00.360516 or earlier. Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- Linksys E8450
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, persistent backdoor installation, network traffic interception, and lateral movement to other devices on the network.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept network traffic, or use the device as part of a botnet.
If Mitigated
Limited impact if device is behind firewall with restricted WAN access and proper network segmentation is implemented.
🎯 Exploit Status
Proof of concept exploit code is publicly available on GitHub. The vulnerability requires no authentication and has a straightforward exploitation path.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available
Restart Required: Yes
Instructions:
No official patch available. Monitor Linksys security advisories for firmware updates. If update becomes available: 1. Download firmware from Linksys support site 2. Access router web interface 3. Navigate to Administration > Firmware Upgrade 4. Upload and apply new firmware 5. Reboot router
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router web interface
Access router web interface > Administration > Remote Management > Disable
Restrict Web Interface Access
allLimit web interface access to specific IP addresses if supported
Access router web interface > Security > Access Restrictions > Configure allowed IPs
🧯 If You Can't Patch
- Isolate affected routers in separate VLAN with strict firewall rules
- Implement network monitoring for suspicious HTTP POST requests to portal.cgi
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface: Status > Router > Firmware Version. If version is 1.2.00.360516 or lower, device is vulnerable.Check Version:
curl -s http://router-ip/status.cgi | grep firmware_versionVerify Fix Applied:
Verify firmware version is higher than 1.2.00.360516 after any update. Test with controlled exploit attempt if possible.📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /portal.cgi with long dut_language parameter
- Unusual process execution or memory errors in router logs
Network Indicators:
- HTTP traffic to router IP on port 80/443 with POST requests containing unusually long parameters
- Outbound connections from router to suspicious IPs
SIEM Query:
source="router_logs" AND (uri_path="/portal.cgi" AND method="POST" AND param_length>1000)